docs: def points_close(a,b):
      '''
      points_close(a,b) yields True if points a and b are close to each other and False otherwise.
      '''
      (a,b) = [np.asarray(u) for u in (a,b)]
      if len(a.shape) == 2 or len(b.shape) == 2: (a,b) = [np.reshape(u,(len(u),-1)) for u in (a,b)]
      return np.isclose(np.sqrt(np.sum((a - b)**2, axis=0)), 0)